1. Field of the Invention
This invention relates to fuse, and more particularly to a fuse capable of surely stopping power supply to a load.
2. Description of the Related Art
A motor vehicle which is a moving body includes a large number of power transmission lines for transmitting power itself and various signals, such as bus bars in electric connection boxes (junction block, relay box, fuse block, etc.), terminals for connectors for electric connection.
The main tendency of the voltage of the power transmitted along the power transmission line is 12 V for a general passenger car, and 24 V (12xc3x972) for a large scale vehicle such as a bus or truck . However, particularly for the passenger car, it has been proposed to adopt a power system for supplying an electric power with a higher voltage value than before in view of demands of improvement in driving efficiency of loads and driving with at an optimum efficiency for each load.
The above power transmission line includes fuse blocks from which a large number of fuses can be removed in order to protect electric circuits for various electric appliances (since the fuse block may have a relay or bus bar, it is referred to as a relay box or junction block, or generally referred to as xe2x80x9celectric connection boxxe2x80x9d. In this specification, the above fuse block, relay box, junction block are generally referred to as xe2x80x9celectric connection block.
The fuse which has been conventionally used for the electric connection block is such a fuse 51 as shown in FIGS. 8 and 9. The fuse 51 includes a pair of terminals 52 arranged in parallel, a housing 54 which houses one ends 53 of these terminals 52 and a fusible body 55 which is formed integrally to the pair of terminals 52 and connect them to each other.
When the fuse 51 is mounted in the electric connection box, the terminals 52 are electrically connected to receiving terminals of the box, respectively. One of the receiving terminals is supplied with an electric power whereas the other thereof is electrically connected to various loads. Thus, the one of the terminal 52 is supplied with the electric power through the receiving terminal whereas the other thereof is connected to the loads. The terminals 52 are housed within the housing 54 in a state where their inner faces 61 are opposite to each other.
The housing 54 is made of insulating synthetic resin. The housing 54 is formed in a box shape. The interior of the housing 54 constitutes a housing chamber within which the one ends of the above pair of terminals 52 are housed.
The fusible body 55 connects the one ends 53 of the terminals 52 to each other. The fusible body 55 is coupled at its both ends with the inner faces 61 which are located at the one ends 53 of the terminals 52. The fusible body 55 includes a fusing portion 62 which fuses when the current value of the electric power supplied from the one of the terminals 52 exceeds a prescribed current value. The fusible portion 62 is formed to have a small sectional area of the fusible body 55.
Where the fuse 51 thus configured is mounted on the electric connecting box, when the current value of the electric power supplied from the one of the terminals 52 through the one receiving terminal exceeds the prescribed current value, the fusing portion 62 of the fusible portion 55 fuses to stop supply of the electric power to the load.
In the fuse 51 shown in FIG. 8, since the fusible 55 is coupled with the opposite inner faces of the terminals 52, there is a relatively small space 60 (FIG. 8) in which the fused potion 62 of the fusible body 55 formed between the inner faces 61 within the housing chamber can scatter. Further, it is generally known that the fusing portion 62 of the fusible body 55 scatters higher momentum as the current value in fusing increases.
In the above conventional fuse 51, when the fusing potion 62 of the fusible body 55 fuses with a higher current value than before, it scatters with higher momentum. In this case, the fusible body 55 thus fused may be deposited on the inner faces 61 constituting the space 60, i.e. surfaces of the terminals 52.
Thus, the fuse deposited may short-circuit the terminals to each other within the space 60. This means difficulty of assuring the insulation between the terminals 52. In this case, supply of the electric power to the load which should be stopped may continue, and therefore the electric power with an excessive current value may be supplied to the load.
An object of this invention is to provide a fuse which can surely stop supply of an electric power to a load when the electric power with the current which exceeds a current value of fusing a fusible body is supplied.
In order to attain the above object of this invention, in accordance with this invention, there is provided a fuse including a pair of terminals arranged in parallel, a housing having a housing chamber for housing respective one ends thereof and a fusible body for coupling the pair of terminals with each other, wherein the other ends of the pair of terminals are exposed from the housing and at least one of the pair of terminals has an interval increasing portion where the interval between the one ends of the terminals is made longer than that between the other ends of the terminals.
In this configuration, since the interval between the one ends of the terminals is longer than that between the other ends of the terminals, the space where the fusible body can be scattered more widely.
Preferably, the housing includes protecting portion for protecting the inner faces of the opposite one ends of the pair of terminals. This prevents the fused fusible body from being deposited on the inner face of the terminal.
Preferably, the housing includes a pair of inner walls opposite in a direction vertically crossing the direction the pair of terminals are arranged in parallel, and the protecting portion is walls which extend from the one of the inner walls to the other thereof. In this configuration, since the protecting portion is walls which extend from the one of the inner walls to the other thereof, the inner face of the one end of the terminal can be protected more surely.
A plurality of fuses are mounted in an electric connection box, and adjacent ones of the fuses are insulated from each other by an insulating means. In this configuration, the fuses can be connected to an appliance and load connected to the electric connection box in accordance with a desired pattern.
Preferably, the insulating means is an outer wall of the housing. Therefore, adjacent ones of the fuses mounted in the connection box are insulated from each other more surely.
the housing includes an outer wall having a window from which the one end of each the terminals is exposed externally.
In this configuration, assuming that the width of the fuse itself in a direction the terminals are arranged is fixed, the interval between the terminals can be increased. In addition, assuming that the interval between the terminals in a direction the terminals are arranged is fixed, the width of the housing in this direction can be decreased.
The above and other objects and features of the invention will be more apparent from the following description taken in conjunction with the accompanying drawings.